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Ozone Depletion

﻿Scientific Article: The Ozone Layer The Ozone layer is located in the Earth’s upper atmosphere. It acts as a barrier and absorbs majority of UV radiation before it hits Earth’s surface. Ozone is made up of three oxygen atoms that are naturally occurring molecules. The depletion of the ozone has become a worldwide issue and is caused by the release of CFCs into the atmosphere. CFCs release chlorine atoms which break down ozone molecules. The depletion of the ozone layer threatens to leave life on Earth unprotected from UV radiation. Chlorofluorocarbons (CFCs) contain chlorine, fluorine and carbon atoms. CFCs can be found in spray cans, in the plastics industry and in refrigerants. When UV rays in the upper atmosphere hit CFC molecules, a carbon-chlorine bond breaks leaving a single chlorine atom. This chlorine atom reacts with the ozone molecule causing it to breakdown. The breakdown of ozone leaves an ordinary oxygen molecule (O2) as well as a chlorine monoxide molecule. Because UV radiation breaks oxygen molecules into single oxygen atoms, the single oxygen atom then breaks up the chlorine monoxide. With the chlorine atom left by itself, it is then able to repeat the process of breaking down more ozone molecules. However, the depletion of the ozone is not only caused by CFCs. Halons, CH3CCI, CCI4, HCFCs, hydrobromofluorocarbons and methyl bromide are all linked with ozone depletion leaving life on earth vulnerable to the effects from exposure to UV radiation.

With the depletion of the ozone, UV radiation becomes more accessible to life on Earth and effects from this radiation follow. Since ozone filters UV radiation, with ozone depletion comes higher levels of UV radiation hitting the surface of the Earth. The increase in ultra-violet rays consequently mean higher risk of skin cancers and cataracts in humans and animals. Higher levels of this radiation also damages materials such as plastics, harm certain crops as well as marine animals. Extra UV...

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...ISSUES AND CONCERNS ABOUT THE OZONE LAYER DEPLETION
INTRODUCTION
The ozone layer protects the Earth from the ultraviolet rays sent down by the sun. If the ozone layer is depleted by human action, the effects on the planet could be catastrophic. In recent years, the ozone layer has been the subject of much discussion. And rightly so, because the ozone layer protects both plant and animal life on the planet. The atmosphere is divided into five layers: the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere. The troposphere is the layer closest to earth and is where all weather happenings occur. The stratosphere is located directly above the troposphere, about 10-50 kilometers above the planet, and houses the ozone layer at an altitude of 20-30 kilometers. The mesosphere is located approximately 50-80 kilometers above the earth, while the thermosphere rests at an altitude of approximately 100-200 kilometers above the earth’s surface. Finally, the boundary of the outermost layer, the exosphere, extends roughly to 960-1000 kilometers above the earth.
Figure 1: Earth's atmosphere is divided into layers, which have various characteristics.
The ozone levels have decreased to a normal level. Normal meaning the levels have dropped from the levels reported in 1980. The ozone layer is an important and fragile part...

...effects the immune system, and harms plant and animal life. For that reason the atmosphere and the ozone layer within it are crucial to a stable life on this planet. The ozone layer is in danger, however. It is facing depletion by a toxic man-made substance called chlorofluorocarbons (CFCs). Together the international community is working through treaties and conventions to stop this environmental problem.
To understand the problem behind ozonedepletion we first must understand what ozone is and how it works. Ozone is a thin protective layer that starts nine miles up in the air and continues up in the sky thirty-one miles (Kellner 20). It serves as a screen against the sun’s harmful UV rays by protecting plants and animals, as well as people from skin cancer, immune system problems, and eye disorders, such as cataracts (Ozone Treaties). Ozone is a gas, often a bluish color, made up of three oxygen atoms instead of the typical two. Ozone forms when solar ultraviolet rays and oxygen molecules meet. The result of the meeting is free oxygen molecules that form to regular oxygen molecules to create ozone molecules. Thus the process repeats (Vorlat 361). So in essence the sun’s rays are destroying oxygen molecules to create the ozone that is going to serve as a filter for the planet. It is a cyclical process...

..."In nature there are neither rewards nor punishmentsthere are consequences."
Robert G. Ingersoll (1833 - 1899)
The ozone layer plays an important role in the atmosphere. It protects life on earth from the full force of the sun's cancer-causing ultraviolet radiation. However, many household products and appliances release substances to the atmosphere that causes the hole in the ozone layer. Chlorofluorocarbons (CFCs), used as refrigerants and aerosol spray propellants, is the main cause of ozonedepletion. When these chemicals are released into the atmosphere, it is broken down by sunlight and destroys the ozone layer. Ozonedepletion may lead to serious problems not only to environment and materials but also in human health.
Effects on human health. Ozonedepletion decreases the atmosphere's natural protection from harmful ultraviolet rays and an increase in the risk of health effects. Ultraviolet rays cause nonmelanoma skin cancer, this type of cancer if left untreated, can spread throughout the body causing disfigurement and more serious health problems. Rays can also cause premature aging of the skin which can later on lead to squamous cell carcinoma.
Ozonedepletion can lead to cataracts and other eye problems. Cataracts are a form of eye damage in which a loss of transparency in the lens of the eye...

...James Gieselmann
Environmental Issue
4/6/14
OzoneDepletion
According to Geir Braathan, the size of the hole in the ozone layer is both approaching an all time high and is continuing to grow. What is the ozone exactly? The average person is unable to answer that question. It is is colorless gas found at a higher altitude in the atmosphere of our Earth. It is formed by oxygen molecules that absorb ultraviolet photons and undergo a chemical reaction known as photolysis. This foreign process is when a single molecule of oxygen breaks down into two atoms. The atom then combines with a molecule to form an ozone molecule. It is located four to ten miles above the surface of the earth. The ozone itself is characterized by a diatomic molecule, constructed by three bonded atoms which differs from the oxygen we breathe because the gas we breathe is only two molecules. If one were to smell this layer, it would seem like a burning electrical wire. The ozone layer protects us and is a vital layer of the earth. The ozone molecules, absorb ultraviolet rays between 310 to 200 nm (nanometers) wavelength, which prevents harmful radiations from entering the Earth’s atmosphere. The process of absorption of harmful radiation occurs when ozone molecules split up into a molecule of oxygen, and an oxygen atom. The oxygen atom, again combines with the oxygen molecule...

...Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. So in short, without the ozone layer everything on earth will burn. The ozone layer is just as important to us as oxygen, without it the harmful UV radiation would give us server burns and destroy our delicate ecosystems.
Even though there is hard evidence that proves that ozonedepletion is harmful for organisms on earth, there are a few groups who think that the ozone layer is a “myth” aka doesn’t exist, others say that with or without the ozone layer life on earth will continue. But, they are wrong!
Credibility: According to Dr. Jack Fisherman, senior research scientist in the Science Directorate at NASA Langley Research Center, “Despite emission controls that have resulted in notable reductions in many American cities, O3 concentrations in non-urban areas in both the U.S. and around the world are increasing, with negative impacts to all living things.” In determining that the depletion of the ozone layer is bad for the humans, plants, and animals.
A Brief summary of what the ozone is and how it’s being depleted.
The ozone layer is a layer 10 meters above earth’s surface. It is made up of 3 oxygen atoms and it protects us from radiation by reflecting most of the harmful radiation back into the atmosphere....

...Figure 2: Sample Essay
The Ozone Layer
(1)
PARAGRAPH 1 (DEVELOPED FROM THE CRITICAL QUESTION AND KEY TERMS)
Problems with ozone can teach us about human effects on our environment. The ozone layer
is an invisible layer of gas that shields us from UV radiation. UV radiation is ultraviolet radiation, or
rays of the sun that can harm living things. One problem today is that the protective ozone layer
around the earth is being destroyed (PROBLEM).
(2)
PARAGRAPHS 2, 3 & 4 (DEVELOPED FROM SMALLER SUPPORTING QUESTIONS)
In the past, the ozone layer protected the earth from UV rays. Now, the ozone layer is being
destroyed by CFCs (CAUSE), or chlorofluorocarbons which are chemicals used in products we use
CFCs are used to manufacture cleaning products, foam in plastic containers, refrigerator coolants and
spray cans.
(3)
There are several effects of this destruction (EFFECTS). First, physical harm such as skin
cancer and cataracts can happen. Second, there can be environmental damage to crops and also to
plants in the ocean food chain. Third, weather patterns can be disrupted. In addition, the earth can be
heating up; this is also called the greenhouse effect.
(4)
Several solutions have been tried (SOLUTIONS). First, here have been voluntary cutbacks
on the use of products containing CFCs. For example Macdonald’s stopped using foam containers.
Second,...

...hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon.
The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents. The manufacture of suchcompounds has been phased out by the Montreal Protocol because they contribute to ozonedepletion.
Applications:
Applications exploit the low toxicity, low reactivity, and low flammability of the CFCs and HCFCs. Every permutation of fluorine, chlorine, and hydrogen based on methane and ethane has been examined and most have been commercialized. Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine. Uses include refrigerants, blowing agents, propellants in medicinal applications, and degreasing solvents.
Environmental impacts
As previously discussed, CFCs were phased out via the Montreal Protocol due to their part in ozonedepletion. However, the atmospheric impacts of CFCs are not limited to its role as an active ozone reducer. This anthropogenic compound is also a greenhouse gas, with a much higher potential to enhance the greenhouse effect than CO2.
Infrared bands trap heat from escaping earth's atmosphere. In the case of CFCs, the strongest of these bands are located at the spectral region – referred to as...

...The Effects of Ozone Pollution
The term "ozone" has appeared in numerous magazine and newspaper articles and has been a subject of discussion on both radio and television. Despite all the publicity surrounding this term, however, many people are still confused by it. The confusion arises from the fact that ozone is both beneficial and harmful. We know that the ozone layer in the upper atmosphere acts as a filter for the sun's ultraviolet rays, reducing the amount of radiation that reaches the earth's surface. At ground level, though, high concentrations of ozone can be harmful.
The Ozone Layer
Ozone gas forms a layer all around the earth high in the stratosphere. It serves as a vital and effective protective barrier from the sun's ultraviolet rays. In recent years, scientists have sounded alarms internationally about the depletion of the ozone layer, citing chemical pollution as the major cause.
A specific class of chemical compounds called chlorofluorocarbons (CFCs) are most often identified as ozone destroyers. CFCs were once widely used in everything from air conditioner coolants to the propellant in aerosol cans but have now been banned in most developed nations, including the U.S.
Many scientists believe much more needs to be done to protect the ozone layer, and international efforts are ongoing....